mac: ensure ui::Compositor exists for visible RWHVs

content/browser/renderer_host/render_widget_host_view_mac.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/render_widget_host_view_mac.h"
 
 #import <objc/runtime.h>
 #include <OpenGL/gl.h>
 #include <QuartzCore/QuartzCore.h>
 #include <stdint.h>
@@ skipping 579 matching lines @@
     render_widget_host_->SetView(this);
 
   // Let the page-level input event router know about our surface ID
   // namespace for surface-based hit testing.
   if (render_widget_host_->delegate() &&
       render_widget_host_->delegate()->GetInputEventRouter()) {
     render_widget_host_->delegate()
         ->GetInputEventRouter()
         ->AddSurfaceIdNamespaceOwner(GetSurfaceIdNamespace(), this);
   }
+
+  if (!render_widget_host_->is_hidden())
+    EnsureBrowserCompositorView();
 }
 
 RenderWidgetHostViewMac::~RenderWidgetHostViewMac() {
   display::Screen::GetScreen()->RemoveObserver(this);
 
   // This is being called from |cocoa_view_|'s destructor, so invalidate the
   // pointer.
   cocoa_view_ = nil;
 
   UnlockMouse();
@@ skipping 270 matching lines @@
   render_widget_host_->NotifyScreenInfoChanged();
 }
 
 RenderWidgetHost* RenderWidgetHostViewMac::GetRenderWidgetHost() const {
   return render_widget_host_;
 }
 
 void RenderWidgetHostViewMac::Show() {
   ScopedCAActionDisabler disabler;
   [cocoa_view_ setHidden:NO];
-  if (!render_widget_host_->is_hidden())
-    return;
 
   // Re-create the browser compositor. If the DelegatedFrameHost has a cached
   // frame from the last time it was visible, then it will immediately be
   // drawn. If not, then the compositor will remain locked until a new delegated
   // frame is swapped.
   EnsureBrowserCompositorView();
 
+  if (!render_widget_host_->is_hidden())
+    return;
+
   WasUnOccluded();
 
   // If there is not a frame being currently drawn, kick one, so that the below
   // pause will have a frame to wait on.
   render_widget_host_->ScheduleComposite();
   PauseForPendingResizeOrRepaintsAndDraw();
 }
 
 void RenderWidgetHostViewMac::Hide() {
   ScopedCAActionDisabler disabler;
@@ skipping 2533 matching lines @@
 
 // "-webkit-app-region: drag | no-drag" is implemented on Mac by excluding
 // regions that are not draggable. (See ControlRegionView in
 // native_app_window_cocoa.mm). This requires the render host view to be
 // draggable by default.
 - (BOOL)mouseDownCanMoveWindow {
   return YES;
 }
 
 @end